Under Texas parental notification law, minors' abortion rate falls, but risk of late abortion rises.

Abortion rates fell among all teenagers in Texas after a parental notification law for minors took effect in the state at the beginning of 2000, but declines among young women who were subject to the law were greater than declines among those who were not. (1) However, among young women who had an abortion, those who had become pregnant 3-6 months before their 18th birthday were more likely to terminate their pregnancy dunng the second trimester than were those who had conceived after their 18th birthday.

Early studies of the effect of parental involvement laws on minors' pregnancy outcomes yielded conflicting findings, possibly because substantial numbers of young women were able to obtain abortions in neighboring states that had no law. However, the number of states enforcing parental involvement laws has doubled since the early 1990s; minors now have to travel much greater distances to obtain an abortion. Given this situation, such laws may lead to higher rates of birth and delayed abortion among women younger than 18.

To examine this issue, researchers used data from birth and abortion certificates obtained from the Texas Department of State Health Services to compare changes in rates of abortion and birth among minors before and after the law took effect. Because these rates have been declining nationally and in Texas since the early 1990s, the researchers used rate changes among 18-year-olds as proxies for the changes that would have been expected without the law.

In 1998-1999, minors in Texas had an average of 5,769 conceptions each year that ended in abortion and 28,096 that ended in birth. In 2000-2002, those figures were 4,661 and 13,174, respectively.

Rates of abortion among 15-17-year-olds ranged from 6.5 to 18.7 per 1,000 women in the earlier period, and from 5.4 to 14.5 during the later period. The rate for 18-year-olds was 27.7 per 1,000 in 1998-1999 and 15.8 per 1,000 in 2000-2002. Between the two periods, the abortion rate fell by 22% among 17-year-olds, by 25% among 16-year-olds and by 18% among 15-year-olds; the rate among 18-year-olds decreased by 7%. In comparison with the decline among 18-year-olds, those among younger women were 11-20% greater.

Birthrates among 15-17-year-olds ranged from 33.6 to 88.2 per 1,000 women in 1998-1999 and from 30.5 to 83.2 per 1,000 in 2000-2002. The rate for 18-year-olds was 117.9 per 1,000 in 1998-1999 and 112.4 per 1,000 in 2000-2002. Between the two periods, the birthrate decreased by 6% among 17-year-olds, by 9% among 16-year-olds and by 9% among 15-year-olds; the rate among 18-year-olds declined by 5%. In comparison with the decline among 18-year-olds, those among 15-year-olds and 16-year-olds were significantly greater (by 5% in each case).

To compensate for large differences in rates of abortion and birth between older and younger teenagers, the researchers conducted additional analyses limited to teenagers who became pregnant within a few months before or after their 18th birthday The timing of conception in relation to a teenager's birthday determined whether she would attain her majority before her pregnancy became too advanced for her to obtain an abortion.

The decline in the abortion rate among teenagers whose pregnancy occurred 0-3 months after their 18th birthday and the decline among those who became pregnant 0-3 months before their birthday--and would therefore have been able to obtain an abortion by the end of their first trimester--did not differ significantly In contrast, the decline among teenagers who conceived 3-6 months before they became 18--and would have been able to attain an abortion only in their second trimester--was 16% greater. Decreases in the birthrate did not differ significantly among the three groups.

Analyses by race and ethnic group found a significantly greater decline in the abortion rate among minors than among 18-year-olds for Hispanics and non-Hispanic whites, and a significantly greater rise in the birthrate among non-Hispanic whites. No significant differences by age were found among non-Hispanic blacks.

The decline in the odds that minors who became pregnant 3-6 months before their 18th birthday would have an abortion after enforcement of the parental notification law began was 23% greater than the decline among 18-year-olds, and the increase in their odds of having a second-trimester abortion was 34% greater than that among 18-year-olds. No significant increase occurred among younger 17-year-olds, who would not have attained their majority until too late in pregnancy for abortion to be an option.

According to the authors, three-quarters of young women who conceive as 17-year-olds and are exposed to a parental notification requirement give birth as 18-year-olds, and have thus been misclassified as adults in earlier studies. The authors avoid this source of bias--which would lead to an underestimate of the effect of such laws--in the current study by measuring young women's age at conception rather than their age at abortion or birth.

The authors acknowledge that their findings cannot be considered causal because of the observational design of the study Nevertheless, given that the U.S. House of Representatives passed legislation in 2005 that would bar minors

from consenting to an abortion in any state other than their own, and that the Senate is considered likely to approve a similar bill, the researchers argue that their results are "relevant to an assessment of the likely effect of pending legislation" extending such laws.--F. Althaus 

REFERENCE

(1.) Joyce T, Kaestner R and Colman S, Changes in abortions and births and the Texas parental notification law, New England Journal of Medicine, 2006, 354(10): 1031-1038.